Unilateral trade deals with chocolate-producing countries Indonesia, Nigeria and Brazil could remove "punitive tariffs" imposed by Brussels on imports of cocoa-based sweet treats, Vote Leave said.
As much as £1.28 of the cost of a £10 egg was accounted for by such charges, it calculated, which are levied on chocolate products but not raw cocoa beans.
So-called tariff escalation is criticised for discouraging industrial development, the Press Association reports.
Spokesman Robert Oxley said: 'Pro-EU campaigners are constantly rabbiting on about the supposed benefits provided by the EU.
"But consumers will be hopping mad to find out that the EU is actually making Easter more egg-spensive.
"As well as putting up the price of food in supermarkets, the EU's protectionist policies hurt businesses in developing countries who are effectively shut out of our markets.
"If we Vote Leave on 23 June, Easter will taste all the more sweeter next year."